When naturally occurring subterranean pressure from gas, water and the like in an oil reservoir has fallen to a point that a well will not produce oil and gas at the earth's surface by way of such natural pressure, some method of artificial lift is necessary to continue producing liquid oil from that well.
A number of artificial lift techniques can be employed in such a situation, one of the most common being downhole pumps employed at the bottom of the well and operated by reciprocation of a string of sucker rods that extend from the downhole pump to the earth's surface and a pumping unit situated thereat. The pumping unit reciprocates the sucker rod string and the downhole pump thereby actuating the pump. Each well is capped at the earth's surface with a wellhead to contain oil that is pumped to the earth's surface and to direct same through a conduit means (connected to the wellhead) to a collection site. The sucker rod string must necessarily extend out the top of the wellhead to reach the pumping unit. A seal means for preventing oil from passing out of the top of the wellhead where the sucker rod string exits is employed. This seal means is conventionally called a stuffing box because of the stuffing therein that is employed to provide a seal around the sucker rod string to prevent oil leakage. In order to get a better seal at the stuffing box the portion of the sucker rod string that reciprocates through the stuffing box is specially coated and polished to give it a smooth surface. That particular section of the sucker rod string is called the polished rod.
If for any reason the well is not pumped for a period of time the polished rod is not reciprocated through the stuffing box and the packing in the stuffing box can sometimes dry out so that when the pumping unit is again actuated oil can leak past the dried out packing and into the atmosphere surrounding the top of the wellhead. If left leaking for a long enough period of time, this can produce a collection of oil on the ground near the base of the wellhead before the packing is again sufficiently wet to provide a good seal against the polished rod.
This invention provides an apparatus whereby normal pumping with the pumping unit and polished rod can be carried on, but the stuffing box is contained in a manner such that any oil leakage therefrom even under pressure will be caught and contained at the wellhead in a manner such that such leakage does not reach the atmosphere or the ground and is caught in an easily disposable manner.